Alternet

I just got myself an 07 is250. I was actually looking at 2017 is250 but I just love the look of the 06-13 and decided to just find one and do the work to get it into good shape.

So I'm settling in to this awesome car, i'm looking at replacing the dash and have a door panel on its way in the mail.

Right now the car has 150,000 km's (93205 miles) and seems to run really well. Good strong idle. No pulsing, stalling or anything. Shifts amazing. All around feels pretty dam good.

The main problem I'm looking right now is the crazy bad gas mileage. I'm getting like 16L/100km's (14.7mpg) according to the computer.
There has to be issues. But like it seems to run really well. Normally if its fouled plugs or carbon build up you have poor or rough idle or misfires or something...

I figured i would fill up the tank and see how long I got out of it... Full tank got me 320kms. And I was not driving with a heavy foot at all. Thats like 20l per 100km (11.6mpg).

Now I do have to state that for this period of time it was -35 to -40c (-31 to -40f) so not expecting great mileage... But there has to be an issue.

What should I be looking at? At this point with how bad it is I'm not ruling out a brake being stuck or something (but it doesn't drive like one is stuck or anything).

Yodog

If you always use the auto stick feature where you select the range of gears rhe car can use, then it’s possible that you never given your cars ecu to fully complete the internal tests that would give you better fuel economy and optimized power band and reduced emissions? I read before that the moment you switch from drive to the “s” mode where you can have a say at what gears the car can play with, that it cancels any running internal tests.

i kno it is a somewhat far fetched possibility of an idea, but hey we never know you know lol

Alternet

I don't use auto stick or flappy paddles currently . But that is super interesting and great to know. Thanks!

JacobsDad

Pretty typical of a bad EVAP charcoal canister.......

Google Search "Symptoms Of A Bad EVAP Canister"

Maybe lead you to a solution.

Alternet

I dont have any check engine light and no pending codes. Engine seems to be running fine. No rough idle and I have put the foot down during the test drive before I bought it and it seemed like it had some power to it. And no smoke from exhaust.

Is there any way of testing it to see if its failed?

Bichon

Have you done any long trips yet? The combination of cold temperatures and short trips can lead to some pretty awful fuel economy.

Alternet

Well that depends on your definition of long. Work and back mostly. 10kms (6.2 miles) one way. Usually takes 15-20 mins.

valeoray

If it runs well, I would check your tire pressures if not done already. I find tires lose a lot of pressure in the cold.

JacobsDad

THIS........bad EVAP canister won't throw a code if it's full of gasoline......if it's full of gasoline it needs to be replaced.

2013FSport

iTrader: (2)

^^Bingo!

That distance at those temps, is a sure fire way to get poor economy. Especially if it took you more than 6 minutes to get there. That says you're basically parked idling more more than you're moving.

Also, I'd suggest you do the math on distance driven/fuel used and verify car isn't fibbing.

Alternet

So does that mean a bad EVAP valve or canister (or both)? Or is it all one part in the IS?

Alternet

I did the math and a full tank got me only about 320kms.

The driving listed is pretty much all driving. There are not alot of stop lights on my route (just slow driving). Its 15-20 mins of driving each way. Even my toyota aristo (kind of a Lexus gs300) with a 500hp 2jzgtte got better gas mileage then my IS.

Also the temps around now at -2C (28.4f) (we have had some crazy temp swings lately). The gas mileage hasn't gotten any better sadly.

Alternet

Also just to note my cars a/f is sits at a nice 14.x unless I was accelerating and then braked, there by slamming throttle closed. Then you can see 11.x for a few seconds

2013FSport

iTrader: (2)

Can you post up fuel trim data when at a steady speed? The next one would the knock sensor value. If it's less than 20 at a steady state, it could be pulling your timing back and that will hurt you economy.

Tire pressure
No brake drag
Fresh oil
Clean MAF
Clean air filter
Alignment isnt whacky (toe in, toe out excessive).
Carbon build up in the intake

Low speeds equal low gear selection which doesn't get you as far per engine revolution compared to 4th 1:1 and 5th/6th overdrive.

Alternet

My air fuel at steady state going about 60km/h (37mph) with the throttle reported at 26.3% open is 14.55. at this exact moment the short term fuel trim is -3.1% (bank 1) -0.8% (bank 2) and my long term fuel trim was -4.7% (bank1) and 3.1% (bank 2).

as for the knock values i don't have that option on my obd reader on my phone but i have timing advance. at steady state going 60km/h (37mph) the advance is 20-24. if i sit at a light its much lower and bounces around a little between 10-3ish.

i as of yet haven't check tire pressure (i just keep forgetting). but i will get them all with in spec soon if they are not.

I haven't had a chance to lift the car yet and spin the wheels and check for drag (but the car seems to want to pull away from a stop with no effort and i don't see any brake dust building on any of the rims). I will check when i get the chance though.

It had an oil change just before i bought it.

when it warms up a little outside i will take out the MAF and clean it.

air filter is good

Alignment is good because it went through a safety inspection (that is required by my province when a car is being sold and registered to a new person) and that is one of the things that is checked and required.

Carbon build up... I don't really know. I cant rule it out other then to say the car acts completely fine. no idle issues no starting issues. not so much as an odd harmonic in the engine from what i can tell. That said i wont be able to tell until i get a chance to change the plugs and shove a borascope into the cylinders this spring/summer.